For some applications, such as high frequency or radio frequency (“RF”) applications, integrated passive devices may be formed using semiconductor processing technology or it may be desirable to integrate passive devices such as inductors and/or capacitors together with active devices such as transistors using conductive silicon substrates such, as for example, a semiconductor die. However, passive devices may have relatively lower quality factors (“Qs”) when these passive devices are formed on, or in relatively close proximity to, the conductive silicon substrate. In addition, due to parasitic capacitive coupling between these passive devices and the conductive silicon substrate, the frequency of operation of the integrated devices may be reduced. Electrically conductive interconnects or busses may be used to electrically couple different devices within the die and external to the die. The frequency of operation may also be reduced by parasitic capacitive coupling between the interconnects and the conductive silicon substrate.
Further, regions of a semiconductor substrate may be physically and electrically isolated from each other. Additionally, some semiconductor devices, such as power transistors, provide a relatively higher output power, which may be utilized in some RF, industrial, and medical applications. Power transistor designers are continually seeking ways to efficiently increase output power by varying the output voltage and current characteristics of a power transistor. For example, a power transistor may have an increased breakdown voltage to enable the power transistor to operate at a relatively higher voltage and provide a relatively higher output power.
For simplicity of illustration and ease of understanding, elements in the various figures are not necessarily drawn to scale, unless explicitly so stated. Further, if considered appropriate, reference characters have been repeated among the figures to indicate corresponding and/or analogous elements.